conditions for life Flashcards
what does having high atmospheric pressure + suitable temperatures allow?
liquid water
why is a magnetic field importent?
to deflect solar winds
what does distance from the sun affect?
- the length of the year + seasonal change
- temperature
- light levels
what would happen if the earth had a lower gravitational pull?
atmosphere would disperse +
gases would disperse
would would happen if earth didn’t have an iron core?
no magnetic core -> ozone layer = destroyed + atmosphere no longer protected, no deflection of solar winds
what does distance from the sun, the atmosphere and greenhouse gases control?
temperature range
how does earth have an atmosphere?
big enough gravity + magnetic field
what does the tilt of the earth affect?
seasons!
what affects day + night?
earths spin
why is liquid water important for life?
-temperature buffer (high heat capacity)
-solvent - aids substance uptake eg. nutrients
why is having a suitable temperature range importent for life ?
enzyme activity:
temps too high = enzymes denature
temps to low = enzyme activity too low
+ allows existence of liquid water
why is the atmosphere important for life?
-enough co2 for photosynthesis
-enough o2 for aerobic respiration
-enough nitrogen for proteins
-ozone absorbs harmful UV
-greenhouse gases - suitable temps
why are season important for life?
reduce extreme temperatures
why is visible light important for life?
- energy source for photosynthesis
-sense of time
-sense of periodicity
-vision
how did early photosynthetic organisms change the atmosphere?
decrease of co2 + increase in o2 through photosynthesis
formation of ozone
describe how earths atmosphere changed over time
-volcanos released co2, ch4, h2s making the atmosphere
-co2 absorbed in oceans + rain
-co2 decreased + formation of limestone
-co2 stored in sediment
-development of photosynthetic organisms (bacteria) produced oxygen
-oxygen reacts with iron in water
-oxygen allows aerobic respiration
-oxygen forms ozone
-ozone absorbs + protects against UV from sun
-mammals + plants colonize the land
-co2 decrease further
how do plants increase atmospheric humidity?
transpiration
name 2 types of proxy data (for data on climate change)
-dendrochronology
-pollen analysis
what is dendrochronology?
proxy data - trees growth rate changes in a predictable pattern throughout the year in response to seasonal climate
what are some limitations of dendrochronology?
-not super reliable - other factors affect growth eg. water, light
-tree availability only in specific locations, not everywhere
-doesn’t go that far back in time
what is pollen analysis?
proxy data - allows a scientist to determine what plants were living in a particular area at a particular time
name 4 limitations of early methods of measuring earths past conditions
-lack of historical data
-limited reliability of proxy data (natural recorder, not direct evidence)
-limited coordination between researchers
-lack of equipment for accurate measurements
-inability to measure many factors
-lack of data collection in many areas
